X - the number of pencils
y - the number of pens
She has twice as many pencils as she has pens.

Tom borrows a pen, so she has y-1 pens. Now she has ten less pens than pencils.

Set 2y and y+9 equal to each other:
She has 9 pens.
Answer:
21 / 143
Step-by-step explanation:
Given that:
Number of Eastern conference reps = 8
Number of western conference rep = 7
Probability of selecting 3 from Eastern reps and 2 from western reps
Probability = required outcome / Total possible outcomes
Total possible outcomes:
selection to be made = 3+ 2 = 5
Total Number of players = 8 +7 = 15
Total possible outcomes
Using combination formula :
nCr = n! / (n-r)!r!
15C5 = 15! / 10!5! = (15 * 14 * 13 * 12 * 11) / (5*4'3*2*1) = 360360 / 120 = 3003
Total possible outcomes = 3003
Required outcome :
8C3 * 7C2
8C3 = 56 ; 7C2 = 21
8C3 * 7C2 = 56 * 21 = 1176
required outcome / Total possible outcomes
= 1176 / 3003
= 21 / 143
Answer:
wow thats a lot let me write this down
Answer:
20.833 feet
Step-by-step explanation:
The light reflects off the mirror at the same angle that it hits it at. So the triangle formed by the beam and mirror is similar to the triangle formed by Kevin and the mirror.
Therefore, we can write and solve a proportion.
h / 10 = 6.25 / 3
h = 20.833
The beam is 20.833 feet tall.